A typical base station includes a digital unit, a radio unit, and an antenna in one physical system. Such a structure of a base station has limitations to be optimized in a cell design. In order to optimize and improve the cell design, a digital unit and a radio unit are spatially separated and the radio unit is installed at a remote location. For example, a digital unit may be installed in a base station. Multiple radio units may be installed at remote locations with antennas and coupled to the digital unit through an optical fiber. Such structure may reduce dead-spaces or holes in coverage but cannot maximize overall radio network capacity.